DEFICIENCY OF TRANSITIONAL FORMS. 



149 



are periods of relative disturbance. During their con- 

 tinuance the exigency of adaptation and transformation 

 was at its height, both in the vegetal and animal world; 

 the conditions of existence at the same time most un- 

 favourable; the number of individuals in those species 

 which succeed in effecting their transformation is neces- 

 sarily reduced, and could increase again only in the sub- 

 sequent periods of repose. It is therefore not surprising 

 that the catalogue of intermediate forms is so defective; 

 and their scarcity is remarked upon only by those who 

 are determined to feel the want of them. For the estab- 

 lishment of scientific evidence in favour of the doctrine of 

 Descent we have them in superabundance. 



With the supposed deficiency of transitional forms is 

 connected another frequent objection, namely, that in re- 

 peated instances whole groups of kinded species have 

 suddenly appeared. If intermediate morphological and 

 anatomical gradations are elsewhere visible, in these 

 groups, the pterodactyls, birds and others, there is no 

 coherence and connection with any aboriginal species 

 previously or contemporaneously existing. This allega- 

 tion is one of the feeblest and most vapid, if raised after 

 the attempt has been made to account for the absence 

 of intermediate forms. It is only a particular case in 

 the alternative that either all species originated in the 

 natural manner indicated by the perfectly adequate num- 

 ber of transitional forms at hand, or all by miracle. In 

 the cases which are here brought forward as heavy 

 artillery, the gap to the aboriginal species is certainly 

 greater than where there is merely a leap from species 

 to species or to genus. But the explanation given of 

 the less striking intervals scarcely needs extension to suf- 



